Explosion-proof mercury lamp lighting unit



Jan. 16, 1968 D. J. GUNN 3,364,346-

EXPLOSION-'PROOF MERCURY LAMP LIGHTING UNIT Filed Sept. 16, 1966 FIG. I

I9 l l6 53 E y I, I I I INVENTOR. I I DONALD J. GUNN.

ATTORNEY.

United States Patent 3,364,346 EXPLOSION-PROOF MERCURY LAMP LIGHTING UNIT Donald J. Guun, Liverpool, N.Y., assignor to Crouse- Hinds Company, Syracuse, N.Y., a corporation of New York Filed Sept. 16, 1966, Ser. No. 579,860 3 Claims. (Cl. 240-11.4)

This invention relates to explosion resisting lighting units of the type employing a mercury vapor lamp as a light source. The mercury vapor lamp requires a ballast choke in the lamp circuit. In operation, the ballast gencrates an appreciable amount of heat.

Heretofore, the ballast was encapsulated in resin material, or potting compound. This encapsulation, and the manner in which the ballast was mounted in the lighting unit, or separate enclosure, prevented the suflicient transfer of heat from the ballast whereby, during operational periods of substantial length, the ballast became overheated and failed.

In such arrangements wherein the ballast was mounted within the lighting unit, disassembly of substantially the entire lighting unit was necessary in order to replace the defective ballast. Accordingly, the maintenance of such lighting units was costly.

The invention has as an object an explosion resisting lighting unit embodying a structural arrangement whereby the ballast and lamp receptacle assembly is mounted within the body of the unit in heat exchanging relation thereto, and the assembly can be conveniently inserted and removed from the lighting unit.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

In the drawings:

FIGURE 1 is a vertical, sectional view of a lighting unit embodying my invention, with a portion shown in elevation. The supporting member, body and globe assembly are all of symmetrical circular cross section.

FIGURE 2 is a view taken on line 2-2, FIGURE 1.

FIGURE 3 is a view taken on line 3--3, FIGURE 1.

designates an elongated tubular body formed of heat conducting material, such as aluminum. The open upper and lower ends are provided with internal threads. A globe assembly is detachably secured in flame tight relation to the lower end of the body.

The globe assembly, in the form shown, includes an annular member 11 having an upwardly extending cylindrical flange 12. The flange 12 is threaded into the lower end of the body 10, and the annular member 11 is formed with a depending cylindrical flange portion 13, offset radially outwardly from the flange 12 to provide an annular shoulder 14 against which the rim 15, encircling the upper end of a globe 16, is positioned. The rim 15 of the globe 16 is clamped against the shoulder 14 by a ring member 17 threaded into the flange 13. A gasket 18 is positioned between the rim 15 of the globe and the ring 17. A guard 19 may be attached to the flange 13, as by screws 20.

A supporting member 21 is secured to the upper end of the body 10, and is formed with an intern-ally threaded hub 22 for attachment to a conduit 23 containing the feed wires 24, 25, for the unit. The supporting member 21 is formed with an upper externally threaded cylindrical portion 27 which threads into the upper end of the body 10. The member 21 is also formed with an externally threaded lower cylindrical portion 28 which is connected to and spaced downwardly from the upper portion 27 by diametrically positioned ribs 30. The lower cylindrical portion 28 is threaded into a cylindrical flange 31 extending Cir inwardly from the inner surface of the body 10 and spaced downwardly from the upper end of the body. The cylindrical portion 28 is closed by a plug 33 of insulating material. Conductors 35, 37, in the form of terminals, are

embedded in the plug 33 in flame tight relation in respect thereto. With this arrangement, the supporting member 21, in conjunction with the body 10, forms a flame tight compartment 38.

A metal plate 40 is mounted in the body intermediate the support member 21 and the globe assembly. The plate 40 is secured to bosses 41 extending inwardly from the side wall of the body, this attachment being by way of screws 42. A ballast, consisting of an iron core 43 and coils 44, is mounted on the upper side of the plate 40. The core 43 is clamped tight against the plate 40 by a holddown member 45 in the form of a U bolt having its ends extending through apertures in the plate 40 and provided with nuts 46. By this arrangement, the ballast is mounted in heat exchanging relation to the plate 40 which, in turn, is mounted in heat exchanging relation to the body 10. a

A lamp receptacle 47 is attached to the under side of the plate 40, as by a bracket 48. The ends of the bracket 48 are formed with offset flanges 49 attached to the plate by screws 50.

With this arrangement, heat generated by the lamp 53 and the ballast is conducted by plate 40 into the body 10 and is radiated therefrom by its large surface area.

The lighting unit is installed by attaching the canopy, or support member 21 to the conduit 23. The feed wires 24, 25, are attached to the terminals of conductors 35, 37. This hook-up being convenient as the terminals are exposed between the ribs 30 of the supporting members. The body 10 is then threaded onto the supporting member. Thereafter, the conductors 35, 37, are connected to wires 55, 57, extending to the ballast. The output of the ballast is connected to the receptacle 47 by wires 58, 59, extending through an aperture formed in the plate 40. This hookup is made through a work opening formed in the side wall of the body 10 and thereafter closed by a threaded plug 61. The body is also formed with an inspection opening closed by plugs 63, this opening, upon removal of the plug, permitting inspection of the connection of the terminals of the conductors 35, 37.

The lower end of the body 10 is of greater diameter than the plate 40 of the receptacle ballast assembly, whereby upon removal of the globe assembly from the body, the ballast assembly can be removed through the lower end of the body.

It will be apparent from the structure described that the lighting unit is convenient to assemble and to install, and the ballast is contained within the body of the unit in heat exchanging relation therewith.

What I claim is:

1. An explosion resisting lighting unit having a mercury vapor lamp, said unit comprising a metallic tubular body, a globe detachably secured to the lower end of said body and forming a flame tight closure therefor, a supporting member secured to the upper end of the body and being formed at its upper end with means for attachment to a conduit containing the feed wires forthe unit, said supporting member being closed at its lower end and forming in conjunction with the body a flame tight compartment communicating with said conduit, a lamp receptacle and ballast assembly mounted in said body, said assembly comprising a metallic plate detachably secured in said body in heat conducting relation thereto and extending transversely of the body intermediate the closed end of said supporting member and said globe, an iron core ballast mounted on the upper surface of said plate, means clamping the core of said ballast against said plate in heat conducting relation thereto, and a lamp receptacle fixed to the underside of said plate, conductors sealed in the closed end of said supporting member and extending from said compartment'into the area above said assembly, said conductors being connected to said ballast and said ballast be- 5 ing connected to the terminals of the lamp receptacle.

2. An explosion resisting lighting unit as defined in claim 1, and wherein said lamp receptacle and ballast assembly are removable through the lower end of said body upon removal of said globe from the body.

3. An explosion resisting lighting unit as defined in claim 1 wherein said body is formed with a work opening in the said Wall thereof intermediate said support member 4- and said assembly, and a flame tight closure for said work opening.

References Cited UNITED STATES PATENTS 2,051,479 8/1936 Hastings 240-l1.2 3,086,106 4/1963 Andrews 2.40-25 3,225,187 12/1965 Curtin 24025 10 JOHN M. HORAN, Primary Examiner.

NORTON ANSHER, Examiner.

W. M. FRYE, Assistant Examiner. 

1. AN EXPLOSION RESISTING LIGHTING UNIT HAVING A MERCURY VAPOR LAMP, SAID UNIT COMPRISING A METALLIC TUBULAR BODY, A GLOBE DETACHABLY SECURED TO THE LOWER END OF SAID BODY AND FORMING A FLAME TIGHT CLOSURE THEREFOR, A SUPPORTING MEMBER SECURED TO THE UPPER END OF THE BODY AND BEING FORMED AT ITS UPPER END WITH MEANS FOR ATTACHMENT TO A CONDUIT CONTAINING THE FEED WIRES FOR THE UNIT, SAID SUPPORTING MEMBER BEING CLOSED AT ITS LOWER END AND FORMING IN CONJUNCTION WITH THE BODY A FLAME TIGHT COMPARTMENT COMMUNICATING WITH SAID CONDUIT, A LAMP RECEPTACLE AND BALLAST ASSEMBLY MOUNTED IN SAID BODY, SAID ASSEMBLY COMPRISING A METALLIC PLATE DETACHABLY SECURED IN SAID BODY IN HEAT CONDUCTING RELATION THERETO AND EXTENDING TRANSVERSELY OF THE BODY INTERMEDIATE THE CLOSED END OF SAID SUPPORTING MEMBER AND SAID GLOBE, AN IRON CORE BALLAST MOUNTED ON THE UPPER SURFACE OF SAID PLATE, MEANS CLAMPING THE CORE OF SAID BALLAST AGAINST SAID PLATE IN HEAT CONDUCING RELATION THERETO, AND A LAMP RECEPTACLE FIXED TO THE UNDERSIDE OF SAID PLATE, CONDUCTORS SEALED IN THE CLOSED END OF SAID SUPPORTING MEMBER AND EXTENDING FROM SAID COMPARTMENT INTO THE AREA ABOVE SAID ASSEMBLY, SAID CONDUCTORS BEING CONNECTED TO SAID BALLAST AND SAID BALLAST BEING CONNECTED TO THE TERMINALS OF THE LAMP RECEPTACLE. 